1. Field of the Invention
The present invention relates to a seat recline system that includes memory. Memory is a feature that xe2x80x9cremembersxe2x80x9d a seat back""s adjusted position after the seat has been dumped, i.e. pivoted fully forward.
2. General Background and State of the Art
Almost all seat backs of vehicle front seats are adjustable. Occupants can adjust the incline of those seat backs for their comfort.
Dumping is the forward pivoting of the front seat of a two-door vehicle to allow passengers to enter the rear seat or to allow cargo to be stored behind the front seat. Many seats dump by releasing the seat""s adjusting mechanism and then, as a result, lose the previous adjustment. Therefore, returning the dumped seat back to the upright position requires the occupant to readjust the seat back.
U.S. Pat. No. 5,806,932 (1998) (Zhuang) and application Ser. No. 09/230,964, filed Jul. 25, 1997 (Zhuang, Eaton, Lawhead and Parrinello), are examples of earlier seat memory systems. The systems have master and slave units. Each relies on a plate near the pivot point of the seat back. Each plate uses a latch. When the latch is unlatched, the seat back can dump, but when the latch is latched, the entire plate moves for seat back adjustment. A mechanism between the master and slave units coordinates their functions.
Several other devices separate dumping from normal adjustments. Therefore, they maintain their adjustment after dumping. The following U.S. patents teach the concept of separation of dumping from other seat adjustments: Dinkel, U.S. Pat. No. 3,887,232 (1975); Tamura, U.S. Pat. No. 3,593,069 (1976), Kazaoka, U.S. Pat. No. 4,502,730 (1985), and Terada, U.S. Pat. No. 4,660,886 (1987). These devices are quite complex with many cooperating parts. Complexity adds to cost and the chance of failure. Adding more parts also increases the weight of the mechanism, which runs counter to weight reduction strategies favored by vehicle manufacturers.
Many seats use mechanical locks for controlling the great back position. One of the more successful mechanical locks uses a rod moveable longitudinally within a housing. U.S. Pat. No. 3,874,480 (1975) (Porter and Sember), xe2x80x9cFriction Brake Mechanism,xe2x80x9d U.S. Pat. No. 4,577,730 (1986) (Porter), xe2x80x9cMechanical Lock,xe2x80x9d and U.S. Pat. No. 5,219,045 (1993) (Porter and Babiciuc), xe2x80x9cLinear Mechanical Lock with One-Piece Lock Housing,xe2x80x9d are examples of such locks. The housing attaches to a fixed vehicle part, and the rod attaches to a part that can move. Their attachments can be reversed. A coil or clutch spring, which is fixed relative to the housing, has a normal inside diameter slightly less than the rod""s outside diameter. When a release lever acts on the coil spring""s free end, the spring unwinds or uncoils slightly. Unwinding increases the spring""s inside diameter enough to release the rod. Releasing the spring causes it to grip the rod. These locks can be manufactured at low cost, need little or no maintenance and are reliable.
Disclosing and providing a less complex memory seat adjustment and dumping mechanism is a principal object of the present invention. Another object is to disclose and provide a mechanism that can use reliable, inexpensive mechanical locks but still has memory.
The present invention controls reclining and dumping of a seat back. The mechanism uses three mechanical locks. The first, a master mechanical lock, attaches between the seat frame and the seat back. It comprises a housing and a rod that can move within the housing. The rod""s movement pivots the seat back. A locking mechanism within the lock selectively secures or releases the rod. The second mechanical lock is the dumping lock. It also comprises a housing, which attaches to the seat frame. A rod moves within the housing. The third mechanical lock is a slave lock. The housing of the slave lock attaches to the seat back, and the rod that is within the dumping mechanical lock also extends through the housing of this slave lock.
Cables extend between the locks. When the master mechanical lock is opened, the cable also opens the slave mechanical lock. When both locks are open, the rod in the master lock can move within the housing, and the housing of the slave recline lock can move along its rod. When both of those movements can take place, the seat back can pivot and be adjusted.
Another cable connects the dumping mechanical lock with the master mechanical lock. When dumping occurs, the dumping mechanical lock opens, and the cable also causes the master mechanical lock to open. Movement of the rod in the dumping mechanical lock carries along the housing of the slave mechanical lock. The movement of the slave lock, the rod within the dumping mechanical lock and the rod of the master lock allows the seat back to dump. However, the rod does not move within the housing of the slave lock.
The dumping mechanical lock also has a latch mechanism. When the dumping mechanical lock opens, the latch blocks the dumping lock from relocking. However, after the seat back is returned to its upright position, the rod strikes the latch and releases the locking mechanism of the dumping mechanical lock. When the dumping lock relocks, the cable between the dumping lock and the master lock releases so that the master lock can relock also. Accordingly, the rod always has the same locked position within the dumping mechanical lock. During dumping, the slave lock remains locked. Consequently, when the rod is back in its locked position, the slave mechanical lock maintains its adjusted position relative to the rod.
Other objects and advantages of the present invention will be evident from the detailed description of the exemplary embodiment.